JP2002015533A - Servo-track writer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain a servo-signal defect and deterioration, in a servo acquiring ratio due to the change of a relative speed between a flexible disk and a magnetic head in the writing of a servo signal. SOLUTION: The flexible disk 21, held to a spindle 31 rotates at a prescribed rotational speed, and a servo signal is written in the rotating flexible disk 21 by magnetic heads 6 and 7. Here, a control means 100 controls the number of rotations of the spindle, so that the difference of the relative speed of the outer peripheral part and the inner peripheral part of the heads 6 and 7 to the rotation of the flexible disk 21 decreases, and the number of rotations, when the servo signal is wrote on the outer peripheral part of the flexible disk 21 becomes smaller than the rotation number, when the servo signal is written on the inner peripheral part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a servo track writer for writing a servo signal for accurately positioning a magnetic head of a disk drive on a flexible disk.

[0002]

2. Description of the Related Art Conventionally, a magnetic layer is formed on both sides of a disk-shaped base made of a flexible polyester sheet or the like, and a flexible disk on which signals can be magnetically recorded using a magnetic head is used as a magnetic disk medium. It is offered as a kind.

[0003] This flexible disk is usually provided with a hard hub (center core) at the center of a disk, and is provided as a disk cartridge entirely housed in a plastic shell.
Because of the advantage of low cost, it is mainly used as a recording medium for a computer. Among such disk cartridges, in a high-density disk cartridge, it is necessary to position the magnetic head by closed loop control. For this control, it is necessary to prerecord servo signals concentrically on a flexible disk. Is done.

[0004] As a method of recording a servo signal on a flexible disk, a hub of the flexible disk is held by a spindle for rotational drive with setting a disk cartridge on a servo track writer, and a magnetic head is mounted on the flexible disk. Then, a method of writing a servo signal while moving the magnetic head in the radial direction of the flexible disk while rotating the flexible disk by the spindle is generally performed (for example, Japanese Patent Laid-Open No. 9-180).
No. 418).

In writing servo signals to a large-capacity flexible disk, the flexible disk is rotated at a high speed of, for example, 2400 rpm or 3600 rpm to shorten the processing time. that time,
The magnetic head is preferably a floating type head used for a hard disk or the like, and it is preferable to reduce the contact between the flexible disk and the magnetic head.

[0006]

As described above, when the flexible disk is rotated at a high speed at a constant speed and a servo signal is written from the outer peripheral portion to the inner peripheral portion, the relative speed between the flexible disk and the magnetic head becomes equal. Since writing in the outer peripheral portion is faster and writing in the inner peripheral portion is slower, a servo signal defect is likely to occur in the outer peripheral portion, and this causes a decrease in the servo yield in the inner peripheral portion.

[0007] In other words, servo signal failures include phase shift, minute signal loss, weak recording, and the like. The causes of these are local deformation and surface projections on the flexible disk, and In the process, foreign matter in the process and dust in the air adhere, and the magnetic head
When the magnetic head collides with a foreign substance or the like, minute vibrations such as a change in flying height, pitching, rolling, and yawing are generated in the magnetic head, and the flying state of the magnetic head fluctuates. As a result, a defect occurs in a write signal. The higher the relative speed between the flexible disk and the magnetic head, the greater the collision energy and the more likely it is that a signal failure will occur. That is, servo signal failure tends to occur as the spindle speed increases and when writing to the outer peripheral portion of the flexible disk.

From the above point, when the flexible disk is rotated at a constant rotation speed, if the relative speed at the time of writing the servo signal to the outer peripheral portion is set low enough to prevent a servo signal defect, the writing at the inner peripheral portion is performed. In some cases, the relative speed is reduced, the servo yield is reduced, and the manufacturing time required for the servo write processing of one flexible disk is lengthened, resulting in disadvantageous cost.

In view of the above, the present invention has been made in view of the above points, and does not provide a servo track writer which can improve the yield while ensuring a good write state of a magnetic head in writing a servo signal. It is assumed that.

[0010]

A servo track writer according to the present invention, which has solved the above problems, holds a flexible disk on a spindle and rotates the disk at a predetermined rotational speed, and writes a servo signal on the rotating flexible disk by a magnetic head. In the servo track writer, the rotational speed at the time of writing the servo signal to the outer peripheral portion of the flexible disk is such that the relative speed of the magnetic head with respect to the rotation of the flexible disk becomes smaller between the outer peripheral portion and the inner peripheral portion. A control means for controlling the spindle speed so as to be lower than the speed at the time of writing the servo signal to the inner peripheral portion is provided.

The control of the spindle speed is performed by continuously changing the relative speed from the outer periphery to the inner periphery of the flexible disk so as to be constant, or by controlling the flexible disk to a plurality of areas within a certain range from the outer periphery to the inner periphery. It is possible to adopt a method in which the spindle speed is changed step by step in each area.

[0012]

According to the present invention as described above, when a servo signal is written by a magnetic head, the relative speed between the outer peripheral portion and the inner peripheral portion of the magnetic head with respect to the rotation of the flexible disk is reduced. And a control means for controlling the spindle rotation speed such that the rotation speed when writing the servo signal to the outer periphery of the flexible disk is lower than the rotation speed when writing the servo signal to the inner periphery. In the whole area from the outer circumference to the inner circumference, the relative speed with the magnetic head can be set to a speed suitable for writing the servo signal. And the servo yield in the inner peripheral portion can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 is a schematic diagram showing a servo track writer according to one embodiment of the present invention.

The servo track writer 1 is provided with a flexible disk 2 in a set disk cartridge 2.
1 is provided with a spindle 31 which is driven to rotate by a rotation driving means 3 having a motor or the like. The spindle 31 is supported by a main body 30 installed on the surface plate 9, and has an upper end projecting into a center hole of a hub 22 (centre core) fixed to the center of a flexible disk 21 accommodated in the disk cartridge 2. A pin 33 is provided, and an upper end surface thereof is formed as a receiving surface of the hub 22. The hub chuck 32 is provided for chucking by a magnetic attraction force or the like.

It is preferable to use an air spindle as the spindle 31 in order to reduce runout. As the spindle 31 rotates, the hub 22 and the flexible disk 21 chucked by the hub chuck 32
Is maintained at a predetermined rotation speed. The number of rotations of the spindle by the rotation driving means 3 is controlled by a control means 100 described later according to the radial position of the head portions 6b and 7b of the magnetic heads 6 and 7 with respect to the flexible disk 21. In order that the difference between the relative speeds of the outer peripheral portion and the inner peripheral portion becomes small,
The rotation speed when writing the servo signal to the outer periphery of the flexible disk 21 is controlled to be lower than the rotation speed when writing the servo signal to the inner periphery.

In the disk cartridge 2, the flexible disk 21 is rotatably housed in a cartridge case 23 indicated by a chain line. Although not shown, windows for inserting a magnetic head are provided on the upper and lower surfaces of the cartridge case 23. The magnetic heads 6, 7, which will be described later, pass through the windows, and the lower surface (0 surface) and the upper surface (1
Surface), and a shutter member for opening and closing the window is slidably installed.

A clock disk 41 of a hard disk is mounted on the spindle 31 coaxially with the flexible disk 21. A clock signal (reference signal pulse) is recorded and reproduced on the clock disk 41 by a clock head 42, and the rotation angle of the flexible disk 21 is adjusted. The timing detecting means 4 for detecting the reference position is constituted. Clock disk 41 and clock head 4
The clock head 42 is attached to a support member 43 installed on the surface plate 9 for a known hard disk device 2. Further, the timing detecting means 4 determines whether the flexible disk 21
It also has a function as a means for detecting the rotational speed of the spindle, and is used for controlling the spindle rotational speed.

A signal writing means 5 for writing a servo signal is provided on the surface plate 9 (anti-vibration table). The signal writing means 5 includes an upper (one surface side) magnetic head 6 and a lower (zero surface) magnetic head 7 which are arranged so as to sandwich the flexible disk 21 and are vertically opposed to each other. Heads 6 and 7 are attached to head base 53. The head base 53 is supported by a linear guide 52 on a base 51 installed on the surface plate 9 so as to be able to reciprocate toward the center of the spindle 31, and is driven along with the linear guide 52 by driving a VCM (voice coil motor) 54. In addition to the moving operation, the stop positions of the magnetic heads 6 and 7 are accurately controlled by the position control using the laser length measuring device 10.

The laser length measuring device 10 is provided with a reflector 11 on the head base 53 for detecting the positions of the magnetic heads 6 and 7 from the position of the head base 53. The reflector 11 is provided from the laser transducer 12 via the half mirror 13. Is irradiated with laser light, and the reflected light is incident on the receiver 14 via the half mirror 13, the position is detected by the length measurement, and sent to the control means 100 described later. Loads, unloads, seek operations, and the like of the magnetic heads 6 and 7 are performed by control according to the length measurement.
The spindle speed control is performed.

The magnetic heads 6 and 7 on both sides are opened and closed by a known load mechanism (not shown) such as dynamic loading in response to driving of the VCM 54, and the flexible disk 21 in the disk cartridge 2 set on the spindle 31. And is unloaded to the retracted position retracted from this position. The upper magnetic head 6 and the lower magnetic head 7 include head portions 6b, 7b each having a head core having a head gap at the tip of suspensions 6a, 7a.
(Slider) is fixed. The heads 6b, 7
b is urged by a spring urging force of the suspensions 6a and 7a toward the surface of the flexible disk 21 with a weak force,
The air bearing portion floats due to the airflow generated by the flexible disk 21 rotating at a high speed, so that a predetermined gap is maintained between the head gap and the surface of the flexible disk 21.

The disk cartridge 2 is loaded and set into the spindle 31 from above by a supply mechanism such as a robot, and the magnetic heads 6, 7 are inserted into the magnetic head insertion window opened by the shutter opening / closing mechanism.
Is loaded / unloaded.

The control unit 100 controls the rotation of the spindle 31, that is, the flexible disk 21, by the rotation driving unit 3, generates the servo signal to be written by the signal writing unit 5, and controls the writing of the servo signal.
The control means 100 controls the drive of the VCM 54 in accordance with the detection of the clock signal. The control means 100 includes a timing signal (rotation speed signal) for detecting the rotation position of the flexible disk 21 by the clock head 42 of the timing detection means 4, a laser measurement. The signal of the elongate device 10 (head position signal) and other detection signals are input.

The spindle 31 by the control means 100
Is performed, for example, with the characteristics shown in FIG.
As a first control example, the spindle rotation speed T is high and the radius r is large on the inner peripheral side where the radius r from the center of the spindle 31 where the head units 6b and 7b are located is small based on the detection of the laser length measuring device 10. On the outer peripheral side, the spindle speed is feedback-controlled to a target speed set in accordance with the radius r, based on a characteristic A of a solid line that changes continuously (linearly) so that the spindle speed T decreases. Also,
As a second control example, the radius r of the flexible disk 21 is divided into a plurality of regions (for example, three regions) within a certain range from the outer periphery to the inner periphery. The spindle speed T is lower in the intermediate region where the radius r is larger than this, and the spindle speed T is further reduced in the outer region where the radius r is larger. The spindle speed is feedback-controlled to a target speed set in three stages according to the radius r. Thus, the flexible disk 21 is driven to rotate so that the relative speed with respect to the head portions 6b and 7b becomes substantially constant from the outer circumference to the inner circumference.

Next, the write operation of the servo signal of the servo track writer 1 will be described. First, the disk cartridge 2 is supplied by a robot or the like, and the hub 22 of the flexible disk 21 is held by the hub chuck 32 of the spindle 31. Further, the shutter member is opened by the opening / closing mechanism, and the signal writing means 5 is loaded into the magnetic head insertion window opened on the upper and lower surfaces of the cartridge case 23.

On the other hand, the spindle 31 is
The rotation of the flexible disk 21 set on the spindle 31 is caused to rotate by the operation of the rotation driving means 3 based on the instruction of 0. In the loading operation of the magnetic heads 6 and 7, a drive signal is output to the VCM 54 based on a command from the control means 100 to move the head base 53 in the forward direction. In conjunction with this, the upper and lower suspensions 6a and 7a are operated so as to open outward by the operation of the load mechanism.
When the heads b and 7b reach the windows beyond the front end of the cartridge case 23, the heads 6 of the magnetic heads 6 and 7 move.
It is operated so that the surfaces of b and 7b approach the flexible disk 21. Magnetic head 6, which is in the loaded state
7, the head portions 6b, 7b are upper and lower suspensions 6a,
7a is urged toward the flexible disk 21 by the uniform urging force, but floats by the airflow generated by the rotation of the flexible disk 21 against this, and the servo signal can be written while maintaining a predetermined gap. State.

Next, when writing the servo signal, first,
By controlling the position of the CM 54, the head gaps of the upper and lower magnetic heads 6 and 7 are loaded at predetermined radial positions (track positions where servo signals are first written) of the flexible disk 21 and a predetermined signal received from the clock head 42 is received. The servo signal is written to the servo track one round from the reference point. After the writing of the servo signal to the servo track is completed, the seek operation of the magnetic heads 6 and 7 to the next servo track is performed, and the next timing signal is received, and the servo signal is written one round to the next servo track. In this manner, while synchronizing with the clock signal, the seek operation and the write operation for sequentially moving the magnetic heads 6 and 7 by a predetermined distance corresponding to the servo track pitch from the outer periphery to the inner periphery (or from the inner periphery to the outer periphery) of the flexible disk 21 are repeated. Perform servo write. The spindle rotation speed at that time is driven to rotate with a characteristic that changes according to the radial position of the head units 6b and 7b based on the above-described control of the control unit 100.

When the servo writing of all the predetermined servo tracks and other processes are completed, the magnetic heads 6 and 7 are unloaded from the disk cartridge 2 for retreat. In the unloading operation, the magnetic heads 6 and 7 are opened by the operation of the load mechanism accompanying the head base 53 moving backward by driving the VCM 54. In this state, the head base 53 further moves backward and the head part 6b at the tip end is opened. , 7
b moves to the outer position beyond the front end of the cartridge case 23 and retreats to the retracted position. After the rotation of the spindle 31 is stopped, the processed disk cartridge 2 is held and removed by a robot or the like, and a new disk cartridge 2 is set on the spindle 31 to perform servo writing in the same manner.

As described above, according to the servo track writer 1 of this embodiment, the servo signals are written on the flexible disk 21 from the outer peripheral side to the inner peripheral side by moving the magnetic heads 6 and 7 in the radial direction. Part 6b,
By controlling the spindle speed so that the relative speed becomes substantially constant in accordance with the radial position of 7b, the spindle speed is reduced when writing the servo signal on the outer peripheral portion where the relative speed becomes higher, thereby achieving a flexible operation. Disk 21
Micro-vibration of the magnetic heads 6 and 7 due to micro-deformation of the magnetic heads 6 and 7 due to collision with projections, attached dust, etc.
The flying states b and 7b can be obtained, and good servo signal writing can be performed. In addition, when writing the servo signal on the inner circumference side where the relative speed becomes lower, the spindle rotation speed is increased to increase the writing speed and improve the servo yield. The processing can be performed without increasing the manufacturing tact for the servo write processing of the flexible disk. With these, the magnetic head 6,
7 and the reliability of the servo signal is improved, which is advantageous in terms of cost.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a servo track writer according to one embodiment of the present invention;

FIG. 2 is a diagram showing control characteristics of a spindle rotation speed with respect to a radial position;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Servo track writer 2 Disk cartridge 3 Rotation drive means 4 Timing detection means 5 Signal writing means 6, 7 Magnetic head 6a, 7a Suspension 6b, 7b Head unit 10 Laser length measuring device 21 Flexible disk 22 Hub 31 Spindle 32 Hub chuck 41 Clock disk 42 Clock head 52 Linear guide 54 VCM 100 Control means

Claims (1)

[Claims] 1. A servo track writer that holds a flexible disk on a spindle and rotates the disk at a predetermined rotational speed, and writes a servo signal on the rotating flexible disk by a magnetic head. So that the rotation speed at the time of writing the servo signal to the outer circumference of the flexible disk is lower than the rotation speed at the time of writing the servo signal to the inner circumference so that the difference between the outer circumference and the inner circumference is reduced. A servo track writer comprising control means for controlling a spindle speed.